Experimental Studies on Combustion of Cattle Manure in a Fluidized Bed Combustor

1987 ◽  
Vol 109 (2) ◽  
pp. 49-57 ◽  
Author(s):  
K. Annamalai ◽  
M. Y. Ibrahim ◽  
J. M. Sweeten
Keyword(s):  
Fluidized Bed ◽  
Fossil Fuels ◽  
Experimental Studies ◽  
Heat Content ◽  
Fluidized Bed Combustion ◽  
Volatile Solids ◽  
Combustion Technology ◽  
Solids Content ◽  
Combustion Tests ◽  
Fluidized Bed Combustor

Manure from cattle feedlots is a renewable energy source which has the potential of supplementing the existing fossil fuels. But the heat content of manure is rather low. Since, the fluidized bed combustion technology has been used for the energy conversion of marginal fuels, such a technology is being explored for the combustion of feedlot manure. A fluidized bed combustor of 0.15 m (6 in.) diameter was used for the combustion tests on manure. Experiments were conducted with −20 to +20 percent excess air and at bed temperatures ranging from 600°C (1112°F) to 800°C (1472°F). Experimental data revealed that the gasification efficiencies ranged from 90 to 98 percent, while the combustion efficiencies varied from 45 to 85 percent. Higher combustion efficiencies were obtained with decreased volatile solids content of manure. The low combustion efficiencies are attributed to the limited residence time available for the volatiles to burn within the reactor.

scholarly journals Fluidized Bed Combustion: Technology for Efficient Utilization of Biomass Residues

2018 ◽  
Vol 7 (2) ◽  
pp. 73-79
Author(s):  
Vishal Sharma ◽  
Rajeev Kamal Sharma
Keyword(s):  
Fluidized Bed ◽  
Fossil Fuels ◽  
Renewable Energy Sources ◽  
Biomass Combustion ◽  
Fluidized Bed Combustion ◽  
Technical Approach ◽  
Fast Pace ◽  
Combustion Technology ◽  
Alternate Source ◽  
Fluidized Bed Combustor

Fossil fuels are the most common and reliable energy source, which presently fulfill 80% energy requirements all across the world. In the last few decades, over-consumption, fast pace modernization and population growth are some prominent factors which are exploiting the fossil fuels. The degradation of natural resources has gone up at an alarming rate which provoked to look for an alternate source of energy. From all available alternative renewable energy sources, biomass is the only carbon-based sustainable option. But, its diversity makes it a complex and difficult fuel. Among all technologies used for energy generation from the biomass, fluidized bed combustion is emerging as a suitable best option to handle fuel diversity. This article deals with biomass fluidization and its combustion in a fluidized bed. The difficulties encountered during biomass combustion and different solutions for the same have been highlighted. Problems like deposition, corrosion, agglomeration and trace metal emission have been discussed and their remedies to avoid the discontinuity in the operation of biomass-fired fluidized bed combustor. This technical approach will help to reduce environmental problems, improve the economic structure of the nation, and remove obstacles for sustainable energy development.

The Study of Partitioning of Heavy Metals During Fluidized Bed Combustion of Sewage Sludge and Coal

2005 ◽  
Vol 128 (2) ◽  
pp. 104-110 ◽  
Author(s):  
I. Gulyurtlu ◽  
M. Helena Lopes ◽  
P. Abelha ◽  
I. Cabrita ◽  
J. F. Santos Oliveira
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Fluidized Bed ◽  
Bituminous Coal ◽  
Fluidized Bed Combustion ◽  
Sulphur Compounds ◽  
Legal Limits ◽  
Higher Temperature ◽  
Combustion Tests ◽  
Fluidized Bed Combustor

The behavior of Cd, Cr, Cu, Co, Mn, Ni, Pb, Zn, and Hg during the combustion tests of a dry granular sewage sludge on a fluidized bed combustor pilot (FBC) of about 0.3 MW was evaluated. The emissions of these heavy metals from mono-combustion were compared with those of co-combustion of the sludge with a bituminous coal. The effect of the addition of limestone was also studied in order to retain sulphur compounds and to verify its influence on the retention of heavy metals (HM). Heavy metals were collected and analyzed from different locations of the installation, which included the stack, the two cyclones, and the material removed from the bed. The results showed that the volatility of metals was rather low, resulting in emissions below the legal limits of the new directive on incineration, with the exception of Hg during the mono-combustion tests. The partitioning of metals, except for Hg, appeared to follow that of ashes, amounting to levels above 90% in the bed streams in the mono-combustion case. For co-combustion, there was a lower fixation of HM in the bed ashes, mostly originating essentially from the sewage sludge, ranging between 40% and 80%. It is believed that in this latter case, a slightly higher temperature could have enhanced the volatilization, especially of Cd and Pb. However these metals were then retained in fly ashes captured in the cyclones. In the case of Hg, the volatilisation was complete. The bed ashes were free of Hg and part of Hg was retained in the cyclones and the rest was emitted either with fine ash particles or in gaseous forms. In mono-combustion the Hg emissions from the stack (particles and gas) accounted for about 50%, although there was a significant amount unaccounted for. This appeared to have significantly decreased in the case of co-combustion, as only about 15% has been emitted, due to the retention effect of cyclone ashes which presented high quantities of unburned matter, calcium and sulphur.

scholarly journals Fluidized bed combustion with the use of Greek solid fuels

2003 ◽  
Vol 7 (2) ◽  
pp. 33-42
Author(s):  
Emmanuel Kakaras ◽  
Panagiotis Grammelis ◽  
George Skodras ◽  
Panagiotis Vourliotis
Keyword(s):  
Fluidized Bed ◽  
Brown Coal ◽  
Circulating Fluidized Bed ◽  
Pilot Scale ◽  
Thermal Capacity ◽  
Low Rank ◽  
Fluidized Bed Combustion ◽  
Bubbling Fluidized Bed ◽  
Combustion Technology ◽  
Combustion Tests

The paper is an overview of the results obtained up to date from the combustion and co-combustion activities with Greek brown coal in different installations, both in semi-industrial and laboratory scale. Combustion tests with Greek lignite were realized in three different Circulating Fluidized Bed Combustion (CFBC) facilities. Low rank lignite was burned in a pilot scale facility of approx. 100kW thermal capacity, located in Athens (NTUA) and a semi-industrial scale of 1.2 MW thermal capacity, located at RWE's power station Niederaussem in Germany. Co-combustion tests with Greek xylitic lignite and waste wood were carried out in the 1 MWth CFBC installation of AE&E, in Austria. Lab-scale co-combustion tests of Greek pre-dried lignite with biomass were accomplished in a bubbling fluidized bed in order to investigate ash melting problems. The obtained results of all aforementioned activities showed that fluidized bed is the appropriate combustion technology to efficiently exploit the low quality Greek brown coal either alone or in conjunction with biomass species.

Retrofitting 25T/h Pulverized Coal-Fired Boiler Into 35T/h Circulating Fluidized Bed Boiler for Burning Mixture of Coal and Bagasse

2005 ◽  
Author(s):  
Han-Ping Chen ◽  
Xian-Hua Wang ◽  
Shi-Hong Zhang ◽  
De-Chang Liu ◽  
Yu-Hua Lai ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Combustion Efficiency ◽  
Economic Benefits ◽  
Pulverized Coal ◽  
Industrial Wastes ◽  
Pollutant Emission ◽  
Fluidized Bed Combustion ◽  
Circulating Fluidized Bed Boiler ◽  
Combustion Technology

In China, there are a large number of pulverized coal-fired industrial boilers, whose steam capacities are usually relatively small. These boilers can burn only high-grade coal and have low combustion efficiency. Furthermore, the combustion emissions, such as SO2 and NOx, pollute the environment severely. Therefore it is very important and urgent to adopt economically efficient and environmentally friendly technologies to retrofit these boilers. At the same time, there are many industrial wastes, such as bagasse, wood waste, rubbish, petroleum coke and so on, need burning disposal in China. Fluidized bed combustion technology is a kind of clear combustion technology, which has many advantages, such as excellence fuel flexibility, high combustion efficiency, low pollutant emission and good turndown capability etc. So, adopting fluidized bed combustion technology, retrofitting pulverized coal-fired boiler into fluidized bed boiler can realize pure burning various wastes or co-firing with coal, which should have great economic benefits and social benefits. And the application prospect of the method is also extensive. The State Key Laboratory of Coal Combustion has successfully retrofitted a 25t/h pulverized coal-fired boiler into circulating fluidized bed boiler with in-bed tubes and downward exhaust cyclone. The retrofitted boiler can burn mixture of coal and bagasse and the steam capacity reaches 35t/h. This paper presents the retrofitting measures and the operation status of the boiler after retrofitting.

A Simulation Study for Fluidized Bed Combustion of Petroleum Coke With CO2 Capture

2003 ◽  
Author(s):  
Jinsheng Wang ◽  
Edward J. Anthony ◽  
J. Carlos Abanades
Keyword(s):  
Power Generation ◽  
Fluidized Bed ◽  
Petroleum Coke ◽  
Co2 Capture ◽  
Low Cost ◽  
Volatile Content ◽  
Fluidized Bed Combustion ◽  
High Carbon ◽  
Overall Efficiency ◽  
Fluidized Bed Combustor

Petroleum coke is regarded as a difficult fuel because of its high sulphur content and low volatile content. However, its low price and increased production, means that there is a powerful economic stimulus to use it for power generation. In this work, a process simulation has been performed as part of a feasibility study on the utilization of petroleum coke for power generation with low-cost CO2 capture. The proposed system employs a pressurized fluidized bed combustor and a calciner. In the combustor itself, the petroleum coke is burned and most of the CO2 generated is captured by a CaO sorbent under pressurized condition to form CaCO3. The CaCO3 is transported into the calciner where limited proportion of the petroleum coke is burned with pure O2, and calcines the spent sorbent back into CaO and CO2. A nearly pure CO2 stream is obtained from the calciner for subsequent disposal or utilization. The predicted overall efficiency of the combustion is near 40%. The proposed system would also be suitable for firing other high carbon and low ash fuel, such as anthracite.

Emission fluxes of heavy metals from the fluidized bed combustion of fossil fuels

1995 ◽  
Vol 26 ◽  
pp. S655-S656
Author(s):  
J Smolík ◽  
M Hartman ◽  
I Sýkorová ◽  
J Kučera
Keyword(s):  
Heavy Metals ◽  
Fluidized Bed ◽  
Fossil Fuels ◽  
Fluidized Bed Combustion ◽  
Emission Fluxes

Modelling Fuel and Sorbent Attrition During Circulating Fluidized Bed Combustion of Coal

2003 ◽  
Author(s):  
D. Barletta ◽  
A. Marzocchella ◽  
P. Salatino ◽  
S. G. Kang ◽  
P. T. Stromberg
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Surface Wear ◽  
Fluidized Bed Combustion ◽  
Coal Fuel ◽  
Primary Fragmentation ◽  
The Impact ◽  
Constitutive Parameters ◽  
Fluidized Bed Combustor ◽  
Circulating Fluidized Bed Combustion

A simulation model of a circulating fluidized bed combustor, based on a one-dimensional description of bed hydrodynamics and a simplified formulation of the population balance equation on fuel and bed solids, has been set up. The model specifically aims at assessing the extent of fuel and sorbent attrition during circulating fluidized bed combustion of coal. Fuel attrition is modelled as a function of carbon loading and of the relevant operating variables while taking into account primary fragmentation of coal and secondary fragmentation and attrition by surface wear of its char. Modelling of sorbent attrition accounts for primary fragmentation of limestone upon calcination as well as attrition by surface wear of lime. To this end time- and conversion-dependent attrition rate is averaged over the sorbent particle lifetime in the reactor. Attrition submodels and their constitutive parameters are based on previous work by the research group in Naples. Coal char combustion and lime sulphation are modelled considering intrinsic reaction kinetics as well as boundary layer and intraparticle diffusion of reactants. The impact of attrition phenomena on the performance of the fluidized bed combustor is characterized by looking at carbon combustion efficiency, at sulphur capture efficiency, at the balance between bottom and fly ashes. The influence of operating parameters like fuel particle size, Ca/S ratio, gas superficial velocity, extent of air staging is investigated. The sensitivity of results of model computations to the parameters expressing fuel and sorbent attrition is presented and discussed.

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